Fix Linux build: unsafe extern block for Rust 2024

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: crisdosaygo

crates/crypto/src/linux.rs

@@ -144,13 +144,17 @@ pub fn aes_gcm_decrypt(key: &[u8; KEY_LEN], nonce: &[u8], ciphertext_and_tag: &[
 
 // ── OpenSSL FFI ────────────────────────────────────────────────────
 
+#[allow(non_camel_case_types)]
 type EVP_CIPHER_CTX = c_void;
+#[allow(non_camel_case_types)]
 type EVP_CIPHER = c_void;
+#[allow(non_camel_case_types)]
 type EVP_MD = c_void;
+#[allow(non_camel_case_types)]
 type ENGINE = c_void;
 
 #[link(name = "crypto")]
-extern "C" {
+unsafe extern "C" {
     fn RAND_bytes(buf: *mut u8, num: i32) -> i32;
     fn EVP_sha256() -> *const EVP_MD;
     fn PKCS5_PBKDF2_HMAC(